Comment by rcxdude

How so? The functionality of the kernel and of systemd are basically orthogonal: neither really provides features that the others do. There are some interfaces in the kernel which are basically intended to be delegated to one userspace process, like cgroups and the hotplug management done by udev, so talking to them directly as an application or library is probably not a good idea and those processes provide a means of co-ordinating that, but that's a kernel decision and the udev one predates systemd.